Hyperbranched olefin oil-based dielectric fluid

Abstract

The present invention generally relates to a dielectric composition which is a poly-α-olefin or poly(co-ethylene-α-olefin) having a backbone weight average molecular weight less than 10,000 daltons. The dielectric composition uses a metal-ligand complex as a precatalyst and exhibits a hyperbranched structure that enables low viscosity, and therefore good flow characteristics, combined with high fire point due to ability to increase molecular weight via branching rather than backbone growth. Other desirable properties include lowered pour point due to crystallization disruption, and desirable thermal oxidative stability.

What is claimed is: 
     
       1. A method of using a dielectric fluid composition comprising a poly-α-olefin or a poly(co-ethylene/α-olefin) having a weight average molecular weight more than 200 and less than 5,000 daltons (Da) prepared from a process including a step of contacting together (1) a monomer selected from (a) an α-olefin; or (b) a combination of an α-olefin and ethylene; and (2) a catalytic amount of a catalyst wherein the catalyst includes a mixture or reaction product of ingredients (2a) and (2b) that is prepared before the contacting step, wherein ingredient (2a) is at least one metal-ligand complex of formula (I): 
       
         
           
           
               
               
           
         
       
       wherein M is titanium, zirconium, or hafnium, each independently being in a formal oxidation state of +2, +3, or +4; n is an integer of from 0 to 3, wherein when n is 0, X is absent; each X independently is a monodentate ligand that is neutral, monoanionic, or dianionic, or two X are taken together to form a bidentate ligand that is neutral, monoanionic, or dianionic; X and n are chosen in such a way that the metal-ligand complex of formula (I) is, overall, neutral; each Z independently is O, S, N(C 1 -C 40 )hydrocarbyl, or P(C 1 -C 40 )hydrocarbyl; L is (C 1 -C 40 )hydrocarbylene or (C 1 -C 40 )heterohydrocarbylene, wherein the (C 1 -C 40 )hydrocarbylene has a portion that comprises a 2-carbon atom linker backbone linking the Z atoms in formula (I) and the (C 1 -C 40 )heterohydrocarbylene has a portion that comprises a 2-atom atom linker backbone linking the Z atoms in formula (I), wherein each atom of the 2-atom linker of the (C 1 -C 40 )heterohydrocarbylene independently is a carbon atom or a heteroatom, wherein each heteroatom independently is O, S, S(O), S(O) 2 , Si(R C ) 2 , Ge(R C ) 2 , P(R P ), or N(R N ), wherein independently each R C  is unsubstituted (C 1 -C 18 )hydrocarbyl or the two R C  are taken together to form a (C 2 -C 19 )alkylene, each R P  is unsubstituted (C 1 -C 18 )hydrocarbyl; and each R N  is unsubstituted (C 1 -C 18 )hydrocarbyl, a hydrogen atom or absent; R 1a , R 2a , R 1b , and R 2b  independently is a hydrogen, (C 1 -C 40 )hydrocarbyl, (C 1 -C 40 )heterohydrocarbyl, N(R N ) 2 , NO 2 , OR C , SR C , Si(R C ) 3 , Ge(R C ) 3 , CN, CF 3 , F 3 CO, halogen atom; and each of the others of R 1a , R 2a , R 1b , and R 2b  independently is a hydrogen, (C 1 -C 40 )hydrocarbyl, (C 1 -C 40 )heterohydrocarbyl, N(R N ) 2 , NO 2 , OR C , SR C , Si(R C ) 3 , CN, CF 3 , F 3 CO or halogen atom; each of R 3a , R 4a , R 3b , R 4b , R 6c , R 7c , R 8c , R 6d , R 7d , and R 8d  independently is a hydrogen atom; (C 1 -C 40 )hydrocarbyl; (C 1 -C 40 )heterohydrocarbyl; Si(R C ) 3 , Ge(R C ) 3 , P(R P ) 2 , N(R N ) 2 , OR C , SR C , NO 2 , CN, CF 3 , R C S(O)—, R C S(O) 2 —, (R C ) 2 C═N—, R C C(O)O—, R C OC(O)—, R C C(O)N(R)—, (R C ) 2 NC(O)— or halogen atom; each of R 5c  and R 5d  independently is a (C 6 -C 40 )aryl or (C 1 -C 40 )hetero-aryl; each of the aforementioned aryl, heteroaryl, hydrocarbyl, heterohydrocarbyl, hydrocarbylene, and hetero-hydrocarbylene groups independently is unsubstituted or substituted with one or more substituents R S ; and each R S  independently is a halogen atom, polyfluoro substitution, perfluoro substitution, unsubstituted (C 1 -C 18 )alkyl, F 3 C—, FCH 2 O—, F 2 HCO—, F 3 CO—, R 3 Si—, R 3 Ge—, RO—, RS—, RS(O)—, RS(O) 2 —, R 2 P—, R 2 N—, R 2 C═N—, NC—, RC(O)O—, ROC(O)—, RC(O)N(R)—, or R 2 NC(O)—, or two of the R S  are taken together to form an unsubstituted (C 1 -C 18 )alkylene, wherein each R independently is an unsubstituted (C 1 -C 18 )alkyl; and wherein ingredient (2b) is at least one activating co-catalyst, such that the ratio of total number of moles of the at least one metal-ligand complex (2a) to total number of moles of the at least one activating co-catalyst (2b) is from 1:10,000 to 100:1; under conditions such that a product selected from a poly-α-olefin and a poly(co-ethylene-α-olefin) is formed, the product having molecular weight distribution components and a backbone weight average molecular weight (Mw) that are more than 200 Da and less than 5,000 Da, the product including at least two isomers in each distribution component above 300 Da, the method comprising operating at least one of (1) a transformer containing a transformer oil comprising the dielectric fluid composition; (2) a bushing or a transmission or distribution cable containing an insulation fluid comprising the dielectric fluid composition; (3) a switchgear containing a switchgear fluid comprising the dielectric fluid composition; and (4) a telecommunications cable, electronic device, or electrical apparatus containing the dielectric fluid composition. 
     
     
       2. The method of  claim 1  wherein the weight average molecular weight of the poly-α-olefin or poly(co-ethylene/α-olefin) is less than 1500 daltons. 
     
     
       3. The method of  claim 1 , wherein each Z of the metal-ligand complex of formula (I) is O. 
     
     
       4. The method of  claim 1 , wherein R 1a  and R 1b  of the metal-ligand complex of formula (I) are methyl, ethyl or isopropyl. 
     
     
       5. The method of  claim 1 , wherein R 1a  and R 1b  of the metal-ligand complex of formula (I) are fluorine atoms, chlorine atoms, bromine atoms or iodine atoms. 
     
     
       6. The method of  claim 1 , wherein L of the metal-ligand complex of formula (I) is —CH 2 CH 2 —, —CH(CH 3 )CH(CH 3 )—, 1,2-cyclopentane-diyl or 1,2-cyclohexane-diyl. 
     
     
       7. The method of  claim 1 , wherein R 5d  of the metal-ligand complex of formula (I) independently is a 2,7-disubstituted 9H-carbazol-9-yl or a 3,6-disubstituted 9H-carbazol-9-yl, 9H-carbazol-9-yl, wherein each substituent is R S . 
     
     
       8. The method of  claim 1 , wherein R 5d  of the metal-ligand complex of formula (I) independently is a (C 6 -C 40 )aryl that is a 2,4-disubstituted phenyl, wherein each substituent is R S ; 2,5-disubstituted phenyl wherein each substituent is R S ; 2,6-disubstituted phenyl wherein each substituent is R S ; 3,5-disubstituted phenyl wherein each substituent is R S ; 2,4,6-trisubstituted phenyl wherein each substituent is R S ; naphthyl or substituted naphthyl wherein each substituent is R S ; 1,2,3,4-tetrahydronaphthyl; anthracenyl; 1,2,3,4-tetrahydro-anthracenyl; 1,2,3,4,5,6,7,8-octahydroanthracenyl; phenanthrenyl; or 1,2,3,4,5,6,7,8-octahydrophen-anthrenyl. 
     
     
       9. The method of  claim 1 , wherein the contacting of the monomer and the catalyst is at conditions that include a temperature ranging from 40° C. to 300° C. 
     
     
       10. An article selected from the group consisting of (1) a transformer containing a transformer oil comprising the dielectric fluid composition of  claim 1 ; (2) a bushing or a transmission or distribution cable containing an insulation fluid comprising the dielectric fluid composition of  claim 1 ; (3) a switchgear containing a switchgear fluid comprising the dielectric fluid composition of  claim 1 ; and (4) a telecommunications cable, electronic device, or electrical apparatus containing the dielectric fluid composition of  claim 1 .